Manifesting heterozygotes in McArdle disease: a myth or a reality-role of statins.
J Inherit Metab Dis
; 41(6): 1027-1035, 2018 11.
Article
in En
| MEDLINE
| ID: mdl-29926259
ABSTRACT
McArdle disease is an autosomal recessive condition caused by deficiency of the PYGM gene-encoded muscle isoform of glycogen phosphorylase. Some cases of "manifesting" heterozygotes or carriers (i.e., patients who show some McArdle-like symptoms or signs despite being carriers of only one mutated PYGM allele) have been reported in the literature but there is controversy, with misdiagnosis being a possibility. The purpose of our study was to determine if there are actually "manifesting" heterozygotes of McArdle disease and, if existing, whether statin treatment can trigger such condition. Eighty-one relatives of McArdle patients (among a total of 16 different families) were studied. We determined whether they were carriers of PYGM mutations and also collected information on exercise tests (second wind and modified Wingate anaerobic test) and statin intake. We found 50 carriers and 31 non-carriers of PYGM mutations. Although we found existence of heterozygotes manifesting some exercise-related muscle problems such as exacerbated myalgia or weakness, they only accounted for 14% of the carriers and muscle symptoms were milder than those commonly reported in patients. Further, no carrier (whether reporting symptoms or not) showed the second wind phenomenon or a flat blood lactate response to maximal-intensity exercise, both of which are hallmarks of McArdle disease. On the other hand, statin myotoxicity was not associated with muscle symptom onset.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Family
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Glycogen Storage Disease Type V
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Glycogen Phosphorylase, Muscle Form
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Heterozygote
Type of study:
Prognostic_studies
Limits:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Language:
En
Journal:
J Inherit Metab Dis
Year:
2018
Document type:
Article
Affiliation country:
Spain
Publication country:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
/
UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA